A motor assembly is used, for example, for driving a windshield wiper. In this case, the driving motor assembly is connected to a link device. Referring to FIG. 1, the motor assembly generally includes a supporting body 2, a motor 3, a worm 5, and a worm wheel 6. The motor 3 is supported by the supporting body 2. The worm 5 is disposed on an output shaft 4 of the motor 3. The worm wheel 6 is supported by the supporting body 2 to be rotatable engaged with the worm 5. The link device (not shown) is connected to the worm wheel 6. In addition, the windshield wiper (not shown) is connected to the link device. Thus, when the output shaft 4 of the motor 3 rotates, the worm 5 and the worm wheel 6, which is engaged with the worm 5, rotate too. The rotary force of the worm wheel 6 is transmitted to the windshield wiper through the link device so that the windshield wiper reciprocates to wipe out the windshield.
When the windshield wiper reciprocates by the operation of the motor 3, in more detail, at the time when the moving direction of the windshield wiper reverses, a large thrust is generated on the output shaft 4 of the motor 3. Therefore, the thrust of the output shaft 4 of the motor 3 should be supported by the driving motor assembly 1.
Thus, the conventional wiper driving motor assembly 1 includes a bearing member 7, an inner race 8 of which is fixed on the output shaft 4 of the motor 3 using a fixing ring (not shown), as shown in FIG. 1. In addition, as shown in FIGS. 1 through 3, an outer race 9 of the bearing member 7 is fixed on the supporting body 2 to support the thrust generated on the output shaft 4 of the motor 3. An additional bearing sheet 100 is inserted between a side surface of the bearing member 7 and the supporting body 2 as a structure for supporting the thrust generated on the output shaft 4 of the motor 3. The bearing sheet 100 supports elastically the bearing member 7 toward the output shaft 4 of the motor 3. In more detail, as shown in FIGS. 2 and 3, a receiving portion 101 formed on the supporting body 2 includes a first supporting surface 102 and a second supporting surface 103. The outer race 9 of the bearing member 7 contacts the first supporting surface 102, and a part of the bearing sheet 100 contacts the second supporting surface 103 to prevent the bearing member 7 from moving toward the output shaft 4 of the motor 3. The receiving portion 101 prevents the bearing member 7 from moving in a radial direction of the bearing member 7. Therefore, the bearing sheet 100 only prevents the bearing member 7 from moving toward the output shaft 4 of the motor 3.